Summary: NEST Scientific Report 2007-200959
ilicon and Germanium semiconductors are well known for electronic applications.
However Si, Ge and their alloys were not been considered attractive as active
materials in light emitting devices due to the indirect nature of fundamental interband
transitions. The advent of epitaxial growth techniques, has encouraged many attempts to
convert the indirect band gap into a direct band gap exploiting nanostructures engineering
by means of control of growth conditions, system geometry, chemical composition, strain,
bands alignment and external fields.
For this aim, the preliminary theoretical understanding and design of the complete structure
is a key requirement.
We have investigated the electronic and optical properties of Si/SiGe and Ge/SiGe
strained-layer multiple quantum wells grown on SiGe substrates with arbitrary alloy
composition and strain. The good agreement with the experimental results demonstrates
the effectiveness of the adopted theoretical approach based on the tight binding model,
and its potential as precious tool to design realistic three dimensional heterostructures
with desired electronic and optical properties.
understanding of the electronic properties
of semiconductor quantum-confined
structures is a key requirement for the